RangeValuePattern.RangeValuePatternInformation.SmallChange Property

Definition

Namespace:

System.Windows.Automation

Assembly:

UIAutomationClient.dll

Gets the small-change value, unique to the UI Automation element, which is added to or subtracted from the elements Value property.

C#

public double SmallChange { get; }

Property Value

Double

The small-change value unique to the UI Automation element or null if the element does not support SmallChange. The default value is 0.0.

Examples

In the following example, an AutomationElement that supports the RangeValuePattern control pattern has its value incremented or decremented by the control-specific SmallChange value.

C#

SetRangeValue(targetControl[0], rangeValuePattern.Current.SmallChange, 1);

C#

///--------------------------------------------------------------------
/// <summary>
/// Sets the range value of the control of interest.
/// </summary>
/// <param name="targetControl">
/// The automation element of interest.
/// </param>
/// <param name="rangeValue">
/// The value (either relative or absolute) to set the control to.
/// </param>
/// <param name="rangeDirection">
/// The value used to specify the direction of adjustment.
/// </param>
///--------------------------------------------------------------------
private void SetRangeValue(
    AutomationElement targetControl,
    double rangeValue,
    double rangeDirection)
{
    if (targetControl == null || rangeValue == 0 || rangeDirection == 0)
    {
        throw new ArgumentException("Argument cannot be null or zero.");
    }

    RangeValuePattern rangeValuePattern =
        GetRangeValuePattern(targetControl);

    if (rangeValuePattern.Current.IsReadOnly)
    {
        throw new InvalidOperationException("Control is read-only.");
    }

    rangeValue = rangeValue * Math.Sign(rangeDirection);

    try
    {
        if ((rangeValue <= rangeValuePattern.Current.Maximum) ||
            (rangeValue >= rangeValuePattern.Current.Minimum))
        {
            rangeValuePattern.SetValue(rangeValue);
        }
    }
    catch (ArgumentOutOfRangeException)
    {
        // TO DO: Error handling.
    }
    catch (ArgumentException)
    {
        // TO DO: Error handling.
    }
}

C#

///--------------------------------------------------------------------
/// <summary>
/// Obtains a RangeValuePattern control pattern from an 
/// automation element.
/// </summary>
/// <param name="targetControl">
/// The automation element of interest.
/// </param>
/// <returns>
/// A RangeValuePattern object.
/// </returns>
///--------------------------------------------------------------------
private RangeValuePattern GetRangeValuePattern(
    AutomationElement targetControl)
{
    RangeValuePattern rangeValuePattern = null;

    try
    {
        rangeValuePattern =
            targetControl.GetCurrentPattern(
            RangeValuePattern.Pattern)
            as RangeValuePattern;
    }
    // Object doesn't support the 
    // RangeValuePattern control pattern
    catch (InvalidOperationException)
    {
        return null;
    }

    return rangeValuePattern;
}

Applies to

See also

• LargeChange